Good health starts in early life. In early childhood, children in 'healthy' families learn that they can rely on their carers for their physical and emotional wellbeing. This allows the child to develop behaviors and other assets that will enable them to maintain their own wellbeing in later life. When the family safety net is compromised in one or more ways, the emotional and physical development of young children is vulnerable. Early life adversity is a risk factor for adverse cardiometabolic health, and poorer cognitive and physical function - three aspects of healthy aging essential for longevity and the maintenance of independence in old age. Questions remain, however, about the pathways and mechanisms through which the adverse health consequences of early life adversity arise. Most research on this topic comes from studies with health measured at a single age in adulthood. Such studies cannot explore the dynamic relationships between early life adversity and changes in health across the life course. We will investigate this in longitudinal studies with repeated measures of health in 3 cohorts. Using repeated measures of health will enable us to assess whether some people remain resilient to the health effects of early adversity, whether some people with favorable health profiles at earlier ages experience deterioration in mid-life health, and the potential for reversibility, i.e. an improvement in health during mid-life. The role of adversity (.g. abusive or dysfunctional relationships) and resources (e.g. social support) experienced in adulthood also remains uncertain. In all 3 cohorts, we will examine whether adversity and resources in adulthood explain or alter the relationship between early adversity and trajectories of health. Risk factors such as smoking and obesity play a role in the generation of health inequalities, and interventions that reduce these risk factors would reduce the adverse health consequences of early life adversity. However, most of this evidence comes from studies with single measurements of smoking, obesity, etc. In all 3 cohorts, we will use repeated measurements of smoking, alcohol use, physical activity, mental health and personality traits, and explore their role in the relationship between early life adversity and later health. Our approach will enable us to identify detrimental or health-promoting behavioral or psychological trajectories. Finally, insufficient attention has been given in the literature to the biological mechanisms through which early life adversity affects later health. We will estimate the role of two biological processes, DNA methylation and cortisol, in the associations between early life adversity and trajectories of health.